What are the layers of the atmosphere?
atmospheric layers
The atmosphere surrounding the Earth contains many layers that make up it, starting from the surface of the Earth to outer space, and these layers are as follows:
troposphere
The troposphere is the first layer of the atmosphere due to its proximity to the Earth's surface, as it extends at a vertical distance of about 10 km from sea level, but this height is irregular, as it may reach near the equator to 20 km, and it may be Its length is 7 km above the poles during the winter, as the height of this layer above the earth’s surface is affected by different latitudes and seasons, as its height increases in summer while it decreases in winter, and most of the mass of the Earth’s atmosphere is concentrated in this layer where the troposphere contains 75% up to 80 percent of the total mass of the atmosphere, and this layer is considered a place for the occurrence of various weather conditions, as the atmospheric changes that occur on the Earth’s surface are due to this layer, in addition to being the incubator layer for most types of clouds in the atmosphere, and this layer is characterized by high humidity Compared to other layers of the atmosphere, which contain a small amount of moisture, the air pressure, density and coldness in this layer are inversely proportional to the amount of its proximity to the surface of the earth, so the air is warmer near the surface of the earth while The universe has less pressure and density as the altitude increases above ground level.
Many different gases are concentrated in the troposphere, as nitrogen constitutes the largest proportion of it, occupying 78% of the total gases in this layer, while oxygen constitutes 21%, while the remaining one percent is distributed among other gases, including argon, which constitutes a proportion 0.9%, and the troposphere contains most of the water vapor in the atmosphere at a rate of up to 99%, and the concentration of water vapor in this layer decreases with its height from the surface of the earth. Solar energy and thermal radiation from the Earth's surface.
stratosphere
The stratosphere is considered the second layer of the atmosphere, depending on its proximity to the Earth's surface.
The height of the beginning of this layer depends on the different seasons and latitudes. At the equator, it is at a height of 20 km, while in the region of the pole it begins at an altitude of 7 km during the winter season.
This layer extends in the atmosphere to a height of about 50 km, and the bottom of this layer and the troposphere are separated by an area called The tropopause, while the upper region is separated from the layer above it by a region called the Stratopause, and unlike the troposphere, the temperatures in the stratosphere are inversely proportional to the height of the layer, where temperatures become hotter at height In this layer, the stratosphere is a place for jet aircraft to fly, where the air in this layer is stable.
The stratosphere contains what is known as the ozone gas, where there is 85% to 90% of the total ozone in the atmosphere.
Ozone is produced when the oxygen molecule (O2) is exposed to ultraviolet rays from the sun; Where these rays analyze this molecule into oxygen atoms (O) that combine with oxygen molecules (O2) to form what is known as ozone gas (O3), and the stratosphere is not limited to containing ozone gas, as it is a place for the presence of many other gases and compounds such as nitrogen oxides. , nitric acid, sulfuric acid, halogens, and its oxides, as well as some other compounds that may result from volcanic events such as hydrochloric acid (HCl), hydrofluoric acid (HF), and other compounds.
mesosphere
The mesosphere is a layer rich in the presence of many iron atoms and some other minerals, due to the falling meteorites that evaporate in this layer while some of its materials remain in the mesosphere, and this layer contains bright or sparkling clouds at night (in English: Noctilucent clouds) located in areas near the poles at high altitudes, and the mesosphere is characterized by strange lightning-like phenomena that occur at a height of tens of kilometers from thunderstorms that occur in the troposphere layer that lies below the mesosphere, and this layer is characterized by being dry and little moisture, and despite this The phenomena and features available in the mesosphere are considered a somewhat ambiguous layer, as it is difficult to know much about its characteristics, due to the difficulty of accessing various scientific research tools such as weather balloons and aircraft to this high layer, and although the satellites orbit above the mesosphere, it is impossible to identify them. directly on its properties, and scientists were able to deliver some scientific tools to collect some samples from this layer, but these scientific trips It was short and rare.
thermosphere
The thermosphere is the fourth layer of the atmosphere that comes directly above the mesosphere and extends from a height of 90 km above the surface of the planet and rises to about 500 to 1000 km, and the boundary between the thermosphere and the next layer is called Thermopause.
while the boundary between it and the layer below it is called the mesopause, and this layer is known as the layer within which the International Space Station and other space shuttles orbit, and the average temperature in this layer is about 200 degrees Celsius, but this temperature may It increases dramatically during the day, and in some periods when solar activity is high, it may reach 500 degrees Celsius, and the temperatures in the thermosphere vary depending on its height.
In the lower layers of this layer, specifically, those layers that are at a height of 200 to 300 km, the temperatures rise sharply and then settle, and in its upper layers, the thermosphere temperatures range from 500 to 2000 degrees Celsius, but it can reach more than that, and the density of the air is in a layer The thermosphere is very low.
The thermosphere is made up of many different atoms and molecules, where the particles that make up the gases disintegrate as a result of colliding with each other within this layer, this disintegration is according to the chemical properties of each molecule, and the photons of X-rays and ultraviolet rays from the sun work to dismantle these molecules and separate them from While the thermosphere consists of oxygen (O2) and nitrogen (N2) gases, these components vary and change in the upper parts of the thermosphere for nitrogen and oxygen atoms, in addition to an increase in the concentration of atomic and ionic components and ionized gases such as helium and hydrogen at the top of this layer. The percentage of particles decreases as the height of this layer increases, and with the change in height, the ionization processes and their levels, the density of particles, and the chemical composition of the materials vary.
ionosphere
The ionosphere of the ionosphere is one of the layers that overlap with the mesosphere, thermosphere, and exosphere, in addition to parts of this layer that overlap with the Earth’s magnetosphere, and this layer has a variable thickness that increases and contracts according to the amount of solar energy that reaches it and divides the ionosphere.
The ionosphere is named after a group of sub-regions known as D, E, and F, according to the wavelength of solar radiation, and the ionosphere was named by this name due to the presence of high concentrations of ionized and electrically charged particles of ions and electrons in it, and when the charged particles in the ionosphere are affected by the magnetic fields that result from Both the Earth and the Sun, which extend from a height of approximately 48 km from the surface of the Earth to a height that may reach the edge of outer space at an altitude of 965 km, the beautiful phenomenon known as the auroras occurs at the poles of the Earth, and this layer is used to transfer Radio signals and the International Space Station.
It is worth noting that some scientific authorities concerned with the fields of scientific research related to the atmosphere, such as UCAR, believe that the ionosphere is not one of the main layers that make up the different layers of the atmosphere, and this is due to the fact that it is distributed across multiple layers such as the mesosphere and thermosphere, although it has its own properties.
Exosphere
The Exosphere is known as the last layer of the outer atmosphere and farthest from the Earth, and the presence of air molecules in this layer is considered rare, as one molecule can pass through this layer to go out into outer space without colliding with another molecule present in it, if Not being pulled towards the Earth by the forces of Earth’s gravitational force, as well as if it has a sufficient velocity to enable it to exit into outer space. kilometers and this height vary depending on the solar activity that affects the atmosphere, and it is not possible to determine the upper limit at which this layer ends completely, but in theory, it is estimated at a height of approximately 193 thousand kilometers, which is equivalent to half the distance to the moon, and when At such great distances, the amount of radiative pressure of the sun on the hydrogen atoms present there is more than the drag force imposed by Earth's gravity, which produces a phenomenon known as the Earth's corona (in English: Geocorona).
This phenomenon was observed from space at an altitude of approximately 96,560 km.
Atmosphere Overview
The atmosphere is defined as the space surrounding the Earth's surface with all its components, including land, oceans, icebergs, etc., and extends to outer space. It consists of a group of gases, dust, and many particles suspended in the atmosphere, or what are called aerosols.
The density of the atmosphere is directly proportional to its proximity to the surface of the earth. The closer we are to the surface of the earth, the greater the density of the atmosphere, as gravity works to pull gases, dust, and fumes close to the surface of the earth, and what should be noted is that the reason behind the retention of the earth Its atmosphere is the presence of high gravity on its surface, and there are many other giant planets that retain their atmospheres such as Venus and Mars, while the low gravity of other planets has led to the planet losing its atmosphere, as is the case in Mercury, and the Earth’s atmosphere is characterized by containing the water compound in its three states Whether liquid, solid or even gaseous, this matter promoted the development of life on the surface of the globe.
Comments
Post a Comment